[user104658]

It's been offered in schools here for years and I would be very very surprised if it's made any difference to rates of illness over winter. Anecdotally, it doesn't seem to have (in fact, last year at my daughter's school was one of the worst years for decades in terms of winter attendance, with her class half empty more than once). The flu vax is basically pure guesswork; there are countless flu strains, they just make an "educated guess" on which one will be going around each area and give a vaccination for that. If it's another strain it doesn't do anything.